Method for verifying an indirect view system

ABSTRACT

Method for verifying indirect view system provides image capture unit (10) with image sensor (20), image processing unit (30), reproduction unit (40) and reference transducer (50) at a position at the vehicle (60), such that the reference transducer (50) lies in a recording portion of the image capture unit (10) and is depicted on the image sensor (20). The reference transducer (50) is defined at a reference transducer target position (51) on the image sensor (20). Image data of at least one recording portion (11) around the vehicle (60) are captured on sensor (20) and reproduced on unit (40). Then, a reference transducer current position (52) of the transducer (50) is determined on the image sensor (20) and the reference transducer current position (52) is compared with the reference transducer target position (51) to that extent whether reference transducer current position (52) is equal reference transducer target positon (51).

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method for verifying an indirect viewsystem, in particular a recording portion of an image capture unit or aread-out portion of an image sensor of the image capture unit, for avehicle, in particular a passenger car or a commercial vehicle, anindirect view system which is configured for performing the method and avehicle which comprises the indirect view system.

2. Description of the Related Art

In motor vehicles, it is legally prescribed to make so-called fields ofview around a vehicle visible for the driver during driving operation.Which fields of view have to be visible is based on the type of themotor vehicle, such as motorcycles, motor vehicles for transportingpassengers, motor vehicles for transporting goods, etc. The visibilityof the fields of view has to be provided by a device for indirect viewand the fields of view have to be visible for a driver, who sits on thedriver's seat, all the time by using the device for indirect view.Depending on the type of the vehicle and in particular thereon, whichareas around the vehicle can be directly seen by the driver, differentlegal prescriptions require that certain fields of view are permanentlyand reliably visible by using the device for indirect view. In Europeand some countries outside of Europe, the fields of view which have tobe permanently reliably visible for a driver are defined in theUN/ECE-Regulation No. 46. Further relevant norms and regulations,respectively, include, for instance, the ISO 5721, ISO 5006, ISO 16505,ISO 14401 and the EU 167/2013. Besides the legally required fields ofview, often further areas around the vehicle, so-called areas of view,are made visible by the device for indirect view. Areas of view maycontain legally prescribed fields of view.

Commonly, the observation of the fields of view is possible with one ormore mirrors. However, mirrors have some drawbacks. For instance,mirrors merely show objects to the driver which are on the same side ofthe mirror as the driver. Any object behind a mirror can only be shownin a difficult manner by this mirror. In addition, mirrors which aremerely made from flat glass show the driver a small area, unless themirrors are very close to the driver. If they are formed convexly, thisproduces an image distortion. Big vehicles typically have six or moremirrors which are mounted around the outside of the vehicle and the mostof which are distorted and convex, which makes it difficult for thedriver to pay attention to all relevant mirrors at the same time.Nevertheless, despite all of the mirrors, there are typically stillblind spots in the areas of view around these vehicles, that is, theareas in which no fields of view are present.

In recent times, it is becoming increasingly common to consider usingcamera systems as devices for indirect view either in addition to or asa replacement for the mirrors as devices for indirect view. In suchcamera systems, an image is continuously captured and detected andprocessed, respectively, and stored, if so. The (video-) data capturedby the image capture unit are transmitted, e.g., by using a supply unitand optionally after further processing, to a display device located inthe driver's cabin. The display device depicts a view into thecorresponding legally prescribed field of view or a plurality of fieldsof view and optionally supplemental information, such as, e.g., possiblecollision risks, distances to other objects, etc., for the area aroundthe vehicle in a manner that the fields of view are permanently viewableat all times for the driver. At the same time, the view system offers asuperior night vision, more flexible arrangement options and theopportunity to view larger areas of view with a reduced distortion.

Permanently viewable means in this context that the view into the fieldof view is depicted in a timely uninterrupted manner, i.e., notinterrupted by alternatingly showing and hiding the fields of view orparts thereof or by overlaying other representations such that the fieldof view cannot be seen completely. Accordingly, the respective field ofview or the fields of views are shown continuously and in real time onthe display device. This holds at least for fields of view which have tobe permanently visible for all vehicle conditions, in which the ignitionswitch is switched on and/or preferably, e.g., coupled to a sensor whichreceives a corresponding signal, such as a door opening signal or anignition switch signal.

With camera systems as devices for indirect view, cameras and imagecapture units, respectively, are mounted on the vehicle body. Thecameras and image capture units, respectively, capture at least asideward portion of the vehicle environment which corresponds to theportion which would be seen by the driver looking in a common lateralrear mirror or front mirror. In particular, it is desired withcommercial vehicles, to make a flat and horizontal part of the roadsurface with a particular width which extends from a defined distancebehind the ocular points of the vehicle driver to the horizon viewableon each of the driver's side and the passenger's side. The width of thisstripe corresponds, with using of common mirrors in a defined distancebehind the ocular points of the driver, to the field of view of a wideangle mirror (for example, field of view IV as defined in the ECE R46),in a shorter distance behind the ocular points of the driver, to thefield of view of a main mirror (for example, field of view II as definedin the ECE R46) whose predefined viewable width, i.e., the extension inthe vehicle's lateral direction, is smaller than the width of the fieldof view of the wide angle mirror. The areas of a front mirrorcorrespond, for example, to the field of view VI of UN/ECE R46.

In order to, in particular, reliably capture or record, respectively,the area of view of a common wide angle mirror with a camera and animage capture unit, respectively, cameras and image capture units,respectively, are often mounted in a certain distance to the vehiclebody of the vehicle, such as at a distal end of a multipart and hingedcamera arm which is characterized in that its longitudinal extension issignificantly longer than its lateral extension. Further, it may beadvantageous with regard to the capturing of required fields of view tomount such camera arms on positions on the vehicle body which differfrom the usual positions on which common mirrors are mounted. Thus, itmay arise that the camera is mounted to positions on the vehicle bodywhich cannot be viewed by the driver during driving.

However, in particular with such multipart camera arms, it may arisethat the camera—e.g. by collision of the camera arm with an object inthe vehicle environment or by an external impact (displacement of thecamera arm by interference by third parties)—is positioned relatively tovehicle such that one or more fixedly defined recording portions (suchas the mentioned legally prescribed fields of view II and IV or one ormore individually defined areas of view) are no longer or no longercompletely shown. If this concerns solely a small deviation between therecording portions to be shown and the recording portions which areactually shown, it may arise that the driver, in particular if thedriver is not familiar with the vehicle, does not recognize thisdeviation. Thus, he might realize possible dangerous situations, whichare not or only insufficiently captured due to the deviation between therecording portion to be shown and the recording portion which isactually shown, too late or not at all which results in an increasedrisk of collision of the vehicle with other traffic participants orobjects in the vehicle environment.

Actually, fields of view of cameras may only be verified and, if so,adjusted with a very extensive test setup. In this respect, referencetargets are put up in a vehicle test stand between which the vehicle ispositioned such that the reference targets have a fixed geometricalreference to the vehicle. The inaccuracy of the vehicle position andtolerances of the vehicle (e.g. component tolerances, different vehiclebuilt-ups, measurements with and without driver, etc.) render an exactverification difficult and extensive. In particular, for smaller vehiclemanufacturer, a complex verification process is practicable only hardly,since hereby high costs arise and the time slots increase as well.Further, for the driver, this is not realizable on his own or only witha very increased effort, e.g., if such a deviation arises during theoperation of the vehicle. The same disadvantages also arise from repairand exchange processes, respectively, if image capture units arerepaired or exchanged.

A method for determining mounting positions and/or orientations ofseveral cameras of a camera system of a vehicle is known from WO2017/174250 A1. A mirror replacement system for a vehicle is known fromEP 2 692 584 A1. A calibration device and a method for determiningcalibration data is known from DE 10 2018 111 776 A1.

SUMMARY OF THE INVENTION

In view of this, it is an object of the present invention to provide amethod for verifying an indirect view system of a vehicle which allowsto recognize a deviation between a fixedly defined area to be shown onthe reproduction unit and an area which is actually shown on thereproduction unit. In addition, it is an object of the invention toprovide a corresponding view system.

This object is solved with a method for verifying an indirect viewsystem for a vehicle, in particular a passenger car or a commercialvehicle, with the features according to claim 1, a view system for avehicle, in particular a commercial vehicle, which can perform themethod, with the features according to claim 15 and a vehicle, whichuses the indirect view system, with the features according to claim 24.Preferred embodiments are given in the dependent claims.

The invention is based on the idea to reduce the effort which ariseswith a common verification of an indirect view system with an exactorientation of the reference targets relative to the vehicle. Inparticular, with the verification, either the recording portion of theimage capture unit or the read-out portion of the image sensor of theimage capture unit is verified. In this respect, according to theinvention, the reference targets (outside the vehicle, in certainenvironments) are replaced by so-called reference transducers. Thereference transducers are attached to the vehicle body. In this respect,at least one reference transducer is provided per vehicle side such thatit lies in the recording portion of the image capture unit withswitched-on image capture unit and is depicted accordingly on the imagesensor of the image capture unit. The reference transducer, thereby, isdepicted and defined, respectively, at a target position on the imagesensor, if the recording portion corresponds to a target recordingportion. The target position of the reference transducer on the imagesensor corresponds to a position which the reference transducer musthave at an ideal adjustment of the image capture unit in the recordingportion of the image capture unit, such that the required and desired,respectively, fields of view are optimally shown to the driver. In otherwords, the target position of the reference transducer corresponds to aposition on the image sensor in which the reference transducer isdepicted at a best possible adjustment of the recording portion of theimage capture unit on the image sensor, i.e., at an adjustment whichcompletely fulfils the requirements to the viewability of the requiredand wished, respectively, fields of view.

With verification and testing, respectively, whether the indirect viewsystem is adjusted such that its recording portion captures the vehicleenvironment as requested and wished, respectively, the vehicleenvironment is captured in form of image data by an image capture unitwith an image sensor and the current position of the referencetransducer on the image sensor is detected. The current position of thereference transducer on the image sensor corresponds to a position whichthe reference transducer actually has in the currently presentadjustment of the image capture unit in the recording portion of theimage capture unit. After detecting the current position of thereference transducer, the reference transducer current position iscompared by the image processing unit or the driver with the referencetransducer target position. In case of a deviation of the referencetransducer current position from the reference transducer targetposition, either a deviation of the recording portion of the imagecapture unit or the read-out portion of the image sensor of the imagecapture unit from the ideal adjustment of the recording portion of theimage capture unit and the read-out portion of the image sensor of theimage capture unit, respectively, is existent. Thereby, possibly, aninsufficient, e.g. incomplete, recording of the required and wished,respectively, fields of view can exist. If the reference transducercurrent position coincides with the reference transducer target positionon the image sensor, no deviation of the recording portion or theread-out portion of the image capture unit from the ideal adjustment ofthe recording portion and the read-out portion, respectively, of theimage capture unit is existent and the current recording portion of theimage capture unit corresponds to the target recording portion of theimage capture unit. The fields of view are shown as required and wished,respectively. The recording portion of the image capture unitcorresponds to the portion of the vehicle environment which is capturedby the image capture unit and is depicted on the image sensor. Theread-out portion of the image sensor corresponds to the portion of theimage sensor which is selected for reproduction on the reproduction unitand is taken out from the image sensor.

Besides the exact coincidence of the reference transducer currentposition and the reference transducer target position for definition ofthe ideal adjustment of the recording portion and the read-out portionof the image capture unit, also a location of the reference transducercurrent position in a defined portion around the reference transducertarget position may be sufficient for a display of the field of view asrequired or wished. Thus, it is not compulsory necessary that thereference transducer target position and the reference transducercurrent position coincide exactly such that the wished and required,respectively, fields of view may be reliably displayed on thereproduction unit. The provision of a defined portion/area around thereference transducer current position may either occur on the imagesensor or on the reproduction unit and serves for balancing/compensatingof mechanical tolerances of the system or vehicle components or ofinaccuracies during image recognition.

Such a method for verifying an indirect view system has the advantagethat the fixed geometric reference between the reference target and thevehicle may be realized in a simple manner by attaching of the referencetransducer directly to the vehicle body without a laborious test setupwith mobile reference targets. Furthermore, by means of the methodaccording to the invention, it is no longer necessary to examine/checkthe vehicle in a suitable examination environment, such as a workshop.Rather, the method may be performed independently on the location of thevehicle, preferably occasionally repeatedly and also preferably duringthe operation of the view system, either automatically (e.g. in fixedtime intervals) or if required (e.g. if the driver wishes). This reducesnot only the necessary equipment for the requested test setup, but isalso time-saving with regard to the installation of the test setup andthe examination/checking itself and, thus, results in an uninterruptedand, thus, economic operation of the indirect view system.

Preferably, the reference transducer target position has a fixedgeometric relation to at least one of the target fields of view capturedby the image capture unit. The target field of view may be a legallyprescribed field of view such as defined in the UN/ECE R46, or may be afield of view which is defined by the manufacturer and user,respectively, and, thus, is a wished field of view. A fixed geometricrelation between the reference transducer target position and the targetfield of view ensures that the reference transducer is positioned in therecording portion of the image capture unit such that the prescribed orwished field of view is shown, if the reference transducer currentposition coincides with the reference transducer target position. Inthis respect, the prescribed or wished field of view is dependent on thetype of the vehicle and its geometry.

According to a preferred embodiment, at least the reference transducercurrent position is depicted on the reproduction unit and the comparisonoccurs on the reproduction unit. Preferably, the comparison of thereference transducer current position and the reference transducertarget position occurs on the reproduction unit by manually applying amask, such as, for example, a foil, or depicting a digital overlay witha fixed reference transducer target position. Thereby, a user, such as,for example, a production associate, applies a mask on which thereference transducer target position is indicated on the reproductionunit and compares whether the reference transducer current position iscovered on the reproduction unit by the reference transducer targetposition on the mask. In case of no coverage, the user recognizes in aneasy manner that the recording portion of the image capture unit isdisplaced or that the read-out portion of the image sensor is displacedand that the requested or wished fields of view possibly are no longercompletely shown. In case of a coverage, however, the user recognizes inan easy manner that the recording portion of the image capture unit orthe read-out portion of the image sensor is adjusted as requested orwished. It is also conceivable to display both the reference transducercurrent position and the reference transducer target position on thereproduction unit. So, it may be quickly and reliably recognized by theuser, without applying a mask, that the recording portion of the imagecapture unit or the read-out portion of the image sensor is displacedand that the requested or wished fields of view are possibly no longershown completely. Both the depiction of the reference transducer currentposition and the reference transducer target position on thereproduction unit may occasionally even occur during driving of thevehicle.

Preferably, the comparison occurs in the image processing unit, e.g., bya certain computing algorithm and a computer program, respectively, forcomparing the reference transducer current position with the referencetransducer target position which is stored in the image processing unit.The computer program may be a graphic program or an image recognitionprogram. With a graphic program, for example, an overlay may beprojected onto the image sensor such that the image processing unit mayrecognize whether the reference transducer current position coincideswith the reference transducer target position. Alternatively, theexamination/checking of a coincidence of the reference transducercurrent position and the reference transducer target position may beperformed by means of image recognition, wherein the image captured bythe image capture unit is segmented and the separate image segments areanalysed by pattern recognition/pattern matching. The comparison of thereference transducer current position and the reference transducertarget position by the image processing unit has the advantage that thecomparison may be performed repeatedly during the operation of theindirect view system and even during driving of the vehicle, uncoupledof an action of the user, which allows a more reliable and more certaincomparison and increases the operational safety of the vehicle, since itmay be quickly recognized if the current and target positions no longercoincide.

Preferably, with the method, not only the reference transducer currentposition and the reference transducer target position are compared witheach other, but it is also at the same examined, whether the currentfield of view which is displayed on the image sensor and, thus, on thereproduction unit is the requested or wished field of view, that is thetarget field of view. The comparison of the current field of view andthe target field of view occurs preferably by position examination, thatis by comparing certain points associated with a target field of viewwith points of the current field of view. So, it may be determined in aneasy manner whether the image capture unit is in operating position or afixedly defined position. For example, in case of a multipart and hingedcamera arm, which may be folded by collision with an obstacle or by anexternal impact by third parties, rotatively, such as, for example, indefined irregular or regular time intervals (e.g. once a day, once aweek or another time interval) or after detection of particular vehiclestates (ignition ON/OFF, engine start, coupling of a trailer, changingimage adjustments, etc.) it may be examined whether the camera arm isdisplaced in view of the ideal orientation or not or whether the cameraarm is located at a predetermined position, such as a folding position,parking position, etc., or not. Therefore, no separate position switchand folding sensor is required in the camera arm for examining/checkingthe viewability of the field of view. The additional comparison ofpositions of fields of view can either be performed always or preferablyon demand, for example, if the vehicle is located in a correspondingtest device with a reference field of view display.

Preferably, the comparison of the reference transducer current positionand the reference transducer target position occurs in the imageprocessing unit in at least an image analysing portion of the imagesensor. The image analysing portion corresponds to a part of the entireimage sensor which the image processing unit uses during applying thecomputer program for comparing the reference transducer current positionand the reference transducer target position. The analysis of a certainpart of the image sensor compared to the analysis of the entire imagesensor saves computing power and computing time. However, it is alsoconceivable to analyse, i.e. to consider, the entire image sensor duringcomparing the reference transducer current position with the referencetransducer target position.

Preferably, the image read-out portion comprises an image analysingportion. The image read-out portion is the portion of the image sensorwhich is shown to the driver on the reproduction unit. According to anembodiment of the invention, the image read-out portion is larger thanthe image analysing portion. According to a further preferredembodiment, the image read-out portion does not comprise the imageanalysing portion, i.e. the image analysing portion is located on theimage sensor in another position than the image read-out portion.

Preferably, the method comprises the additional step of putting-out asignal to the driver if the reference transducer current position isunequal to the reference transducer target position. The signal may bean acoustic, optic and/or haptic signal and may preferably be repeatedlyshown to the driver. An acoustic signal may be one or more of an audiowarning and an alert, respectively, a voicemail, etc. An optic signalmay be one or more of an optical warning notice, such as, for example, ared triangle with exclamation point, on the reproduction unit, in thecar dashboard, in a head-up display, etc. The optical warning notice mayoccur repeatedly, such as a blinking, or can be shown constantly. Ahaptic signal may be a vibration of the steering wheel. Variouscombinations of acoustic, optic and/or haptic signals are conceivable.By the signal(s), the driver may timely, i.e. without noticeable timedelay, recognize that the recording portion of the image capture unit orthe read-out portion of the image sensor has changed.

According to a preferred embodiment, the method may comprise theadditional step of performing a calibration action, if the referencetransducer current position is unequal to the reference transducertarget position. A calibration action is necessary, if the referencetransducer current position is unequal to the reference transducertarget position, in order to bring the wished field of view again intocoincidence with the target field of view. A calibration action means anadjustment and correction, respectively, of a recording portion of theimage capture unit or a read-out portion of the image sensor of theimage capture unit, such that the image capture unit captures therequired and wished fields of view and such that these are shownaccordingly on the image sensor and the reproduction unit. Bycalibrating, the recording portion and the read-out portion of the imagecapture unit cannot only be verified, i.e. cannot be checked forcorrectness, but the recording portion and the read-out portion may alsobe corrected, if required.

The output of a signal and the performing of a calibration action mayoccur separately from each other or in combination. That is, it isconceivable that a signal is put out, in order to point out to thedriver or the production associate a deviation of the referencetransducer current position and the reference transducer targetposition, however without correcting the deviation. Alternatively, nosignal may be put out to the driver or the production associate, butdirectly after determination of a deviation between the referencetransducer current position and the reference transducer targetposition, a correction of the deviation occurs. Further alternatively,the processes of the signal output and the correction may also occurdirectly subsequent.

Preferably, the calibration action comprises the adjusting (calibrating)of the recording portion of the image capture unit or the read-outportion of the image sensor, such that the reference transducer currentposition is equal to the reference transducer target position, i.e.,that the reference transducer current position coincides with thereference transducer target position on the image sensor, i.e. that thereference transducer current position and the reference transducertarget position have the same position on the image sensor. So, it canbe ensured that the driver may reliably view into the vehicleenvironment.

Preferably, the adjusting of the recording portion of the image captureunit or the read-out portion of the image sensor occurs manually orelectrically by aligning at least one part of the image capture unitand/or digitally by adapting the at least one image read-out portion onthe image sensor. Thereby, the orienting of the at least one part of theimage capture unit may occur manually, e.g., by displacing of adjustmentscrews of the image capture unit at the body of the vehicle or of asupporting structure supporting the capture unit. Another example is thedisplacing of the supporting structure and parts of the supportingstructure, respectively, relatively to each other. Alternatively, theorienting may also occur by adhering the capture unit in a suitableposition and posture, respectively, on the body of the vehicle or asupporting structure supporting the capture unit. Further alternativelyor additionally, the orienting of the at least one part of the imagecapture unit may occur electrically, such as, for example, by using aservo motor, which, for example, automatically displaces the optic ofthe image capture unit. The orienting of the image read-out portion mayoccur manually by means of a corresponding input medium, such as ajoystick, a touchscreen, a door control module, input buttons at themonitor, etc., or may automatically occur by a calibration program whichis stored in the image processing unit. Alternatively or additionally,the adaptation of the at least one image read-out portion may occurdigitally by changing the image read-out portion on the image sensorsuch that the reference transducer current position coincides with thereference transducer target position. For example, this may occur bydisplacing the read-out portion on the image sensor pixel by pixel.

The calibration action occurs by a signal received in the imageprocessing unit. Preferably, the signal may be received during theoperation of the indirect view system. The signal may be a manual inputof the user, such as, for example, the driver or a production associate,or may be put out by means of a software in a clocked manner (timeinterval, pattern) or by defined vehicle functions (ignition ON/OFF,engine start, coupling of a trailer, changing image adjustments, etc.).

The target field of view is preferably a legally prescribed field ofview. For example, the target field of view corresponds to one of thefields of view which are defined in the UN/ECE R46, e.g., the field ofview of group II or IV. Legally prescribed fields of view have a fixedrelation to the ocular point of the driver as it is defined in theUN/ECE R46. Thus, in this case, there exists also a fixed geometricrelation between the ocular point of the driver and the referencetransducer which further increases the reliability that the driveractually views into the field of view which he should view into.

Preferably, the indirect view system is a mirror replacement systemwhich completely replaces legally prescribed vehicle mirrors.

According to a further aspect of the invention, an indirect view systemof a vehicle is configured such that it may perform the above describedmethod. The indirect view system comprises at least one image captureunit with an image sensor which is configured for recording image dataof at least one recording portion around the vehicle, at least one imageprocessing unit which is configured for processing the image datacaptured by the image capture unit, and at least one reproduction unitwhich is configured for reproducing the image data processed by theimage processing unit. Further, the indirect view system comprises atleast one reference transducer which is configured such that it isattachable to a defined position at the vehicle and, in a state of theindirect view system mounted to the vehicle, lies in a recording portionof the image capture unit and is displayed on the image sensor, whereinthe reference transducer is displayed at the reference transducer targetposition on the image sensor. Furthermore, the indirect view systemcomprises at least one verification unit which is configured fordefining a reference transducer target position and for determining areference transducer current position on the image sensor.

As image capture unit, any digital image capture units come intoconsideration which have an image sensor and which are suitable torecord/capture the vehicle environment in form of image data, such as,for example, cameras with a CMOS or CCD technology. As image processingunit, any control unit (ECU) comes into consideration which is suitablefor putting out and receiving signals and commands. Thereby, the imageprocessing unit may comprise a single image processing module or aplurality of image processing modules which are either arranged in theview system in one position or at different positions or which arecompletely or partly positioned in the vehicle as well. As reproductionunit, any monitor, any display, etc. comes into consideration which issuitable for showing the image data recorded by the image processingunit, such as a TFT monitor, a LCD monitor, etc.

Preferably, the view system further comprises a calibration unit whichis configured for performing a calibration action. Thus, with theindirect view system, it is not only possible to determine whether thereference transducer current position coincides with the referencetransducer target position or not, but it is also possible, in case of adeviation between the reference transducer current position and thereference transducer target position, to correct the deviation and,thus, to adjust the recording portion of the image capture unit or theread-out portion of the image sensor such that the reference transducercurrent position and the reference transducer target position on theimage sensor and, thus, also on the reproduction unit coincide, i.e.,lie at the same position or at least in a defined area around thereference transducer target position.

Preferably, the reference transducer comprises a geometric pattern. Forexample, the reference transducer may be a crossline, a triangle, acircle, if so, monochrome or polychrome, which can be attached to thevehicle body at a suitable location. Alternatively or additionally, thereference transducer may also be part of the vehicle body, especiallythe vehicle contour, which has a special shape for recognition by meansof image recognition. For example, the reference transducer maycorrespond to an edge at the rear of the vehicle, such as, for example,the driver's cabin or the built-up. Alternatively, the referencetransducer may also be a wheel of the vehicle or a flashlight signal ofthe turning indicator. Alternatively, the special shape may also berecognized by a user on the reproduction unit.

Alternatively or additionally, the reference transducer may beconfigured for reflecting light. For example, the reference transducermay be a reflector, if so, as adhesive label/sticker, or may comprisereflection tapes/ribbons. Thereby, the reference transducer can also berecognized in dark vehicle environments with the presence of lightsources in the vehicle environment on the image sensor or on thereproduction unit.

Alternatively, the reference transducer may be a light source itself.For example, the reference transducer may be an LED, an IR lamp, alaser, a light bulb, etc. Thus, the reference transducer can also berecognized in darkness, such as at night, in a tunnel or at bad weatherconditions, on the image sensor or on the reproduction unit, even if nofurther light source is present in the vehicle environment. Thereby, thelight source can either shine permanently, blink or may switch on onlywith the presence of a particular event, such as with switching on theignition, coupling of a trailer, etc. or maybe manually switched on by auser (e.g. a driver or production associate).

Preferably, the light source may be a lamp which exists at the vehicle,such as, for example, a vehicle boundary lamp, a circumference lamp, arear lamp, an entry lamp, a signal indicator, etc. Even lamps at thevehicle may be used as reference transducer which do not shine towardsthe image capture unit, but notwithstanding lie in the recording portionof the image capture unit, such as for example a boundary lamp at a rearportion of the vehicle or the driver's cabin or the vehicle built-up. Inthis case, an opening has to be provided in the lamp housing throughwhich the light is transmitted towards the image capture unit.

With using a light source as reference transducer, the light source mayfurther advantageously be configured for identifying a pollution of theoptics of the image capture unit on the reproduction unit. Byilluminating the optics of the image capture unit, such as, forinstance, the lens, a foreign particle, if a foreign particle is locatedon the optical element, is well recognizably depicted on the imagesensor, i.e., more clearly than without an additional lighting. Byilluminating the foreign particle, a high contrast and accentuateddepiction, respectively, of the foreign particle is generated directlyon the image sensor and, thus, an alleged pollution of the optic mayeither be identified automatically on the image sensor by imagerecognition or may be shown to the driver on the reproduction unit.

Preferably, the view system comprises at least two capture units. Eachcapture unit is associated with a respective reference transducer.Alternatively, one common reference transducer is associated with thecapture units.

According to a preferred embodiment, the view system is a mirrorreplacement system.

According to a further aspect, a vehicle is provided with the abovedescribed view system, wherein the image capture unit is arranged in aholding element which extends distally from the vehicle. The holdingelement may be a camera arm which is characterized in that it has asubstantially larger extension in the longitudinal direction than in thelateral direction. Preferably, the image capture unit is arranged at anend of the camera arm distally from the vehicle, in order to capture thevehicle environment in a suitable manner. The vehicle is preferably apassenger car or a commercial vehicle. As commercial vehicle, a truckcomes into consideration which has a driver's cabin and a built-up whichis preferably rigid, such as a metal built-up. Alternatively, a truckwith a driver's cabin and a trailer may be comprised by the term“vehicle”, too.

Preferably, the vehicle is a commercial vehicle and the referencetransducer is arranged at an outer side of the vehicle driver's cabin.Alternatively, the reference transducer may also be attached to a sidesurface of the vehicle or the reference transducer may be attached to afront surface of the vehicle. This is in particular advantageous if theECE/UN R46 is applied. Further alternatively, the reference transducermay be attached to a vehicle built-up of the vehicle, e.g., a box bodyor a side board wall.

The reference transducer may be directly attached to the vehicle or maybe attached to the vehicle by means of a reference transducer supportingelement. The supporting element may be a component which protrudes fromthe vehicle in its mounted state, whose end distal of the vehicle isprovided with the reference transducer, such as adhered or screwedthereto.

According to a preferred embodiment, the reference transducer isreleasably connected with the vehicle. In this respect, the referencetransducer is attached temporarily only for the calibration action andwill be removed afterwards, such as, for example, by means of a magneticbase, a screw-on, a hang-up connection, etc. Alternatively, thereference transducer may also be non-releasably connected to the vehiclesuch that it is permanently present at the vehicle, such as, forexample, by an adhesive label/sticker, a painting or a respectivevarnishing, a vehicle lamp, a separate component, a vehicle referencewith contrast to the environment, such as, for example, the rear edge ofthe driver's cabin, the wheel house, etc.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in conjunction withthe accompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims. It should be further understood that thedrawings are not necessarily drawn to scale and that, unless otherwiseindicated, they are merely intended to conceptually illustrate thestructures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described exemplarily based onthe accompanying figures, in which:

FIG. 1 shows a schematic structure of a view system which can performthe method according to the invention;

FIG. 2 shows a plan view of the vehicle with an image capture unit and atarget field of view;

FIG. 3 shows a side view of a vehicle with an image capture unit and atarget field of view;

FIG. 4 shows a reproduction unit which shows the vehicle environmentshown in FIGS. 2 and 3;

FIG. 5 shows an image sensor on which a reference transducer currentposition and a reference transducer target position as well as a currentfield of view and a target field of view are shown;

FIG. 6 shows a reproduction unit which shows the vehicle environmentshown in FIGS. 2 and 3 with a reference transducer at a vehicle sidesurface;

FIG. 7 shows a reproduction unit which shows the vehicle environmentshown in FIG. 6 with a reference transducer respectively arranged in atarget position and in a current position and a corresponding currentfield of view and target field of view; and

FIG. 8 shows a flow diagram which comprises the essential steps of themethod for verifying and calibrating, respectively, an indirect viewsystem according to the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows a schematic view of an indirect view system 1 which canperform the method according to the invention. The view system 1comprises an image capture unit 10, such as a camera, with an imagesensor 20, an image processing unit 30, such as an ECU, and areproduction unit 40, such as a monitor. The view system 1 shown in FIG.1 is shown in an ideal vehicle environment in which a vehicle 60 (seerectangular which is shown with a two dots dashed line) and a targetfield of view 71 associated with the vehicle 60 (see hatchedrectangular) is to be seen. An ideal vehicle environment presently meansthat the target field of view 71 is shown to a driver (not shown) of thevehicle 60 as required on the reproduction unit 40. The forward drivingdirection of the vehicle 60 shown in FIG. 1 runs in FIG. 1 to the right,the rearward driving direction runs in FIG. 1 to the left. The captureunit 10 has a recording portion 11 which, starting at the camera 10,flares and expands, respectively, to the rear side of the vehicle 60.

Further, the view system 1 comprises a reference transducer 50. Thereference transducer 50 is attached in FIG. 1 to a left outer side of aschematically shown vehicle 60.

The target field of view 71 is arranged obliquely behind the vehicle ofa left side of the vehicle 60 and may be a legally required field ofview, such as a field of view of group II or IV, as required in theUN/ECE R46. The target field of view 71 as shown in FIG. 1 has a fixedgeometric reference 73 to the reference transducer 50. That is, thearrangement of the target field of view 71 with reference to thereference transducer 50 is known and is also always unaltered in theideal vehicle environment.

FIG. 2 shows a plan view of a vehicle 60, presently a truck. The vehicle60 has a driver's cabin 61 and a vehicle built-up 62 (e.g. a tipper, acooler, a box body, a car transporter etc.). The forward drivingdirection of the truck 60 runs in FIG. 2 to the left, whereas therearward driving direction of the truck 60 runs in FIG. 2 to the right.The following description of the vehicle environment on the left side ofthe truck 60 also holds for the right side of the truck 60, even if notshown.

The truck has at the left side of the traction machine, in particularthe driver's cabin, an image capture unit 10. The image capture unit 10captures the vehicle environment left alongside and behind the truck 60and has a recording portion 11 which expands in a horizontal plane whichis parallel to the road surface from the image capture unit 10 to therear of the truck 60. The recording portion 11 of the image capture unit10, thus, is named recording cone 11.

Left alongside/next to the truck 60, the target field of view 71schematically shown in FIG. 1 is arranged. The target field of view 71extends in a predetermined distance behind the ocular point of thedriver (not shown) to the rear of the truck 60 and expands in aparticular angle to the rear. Presently, the target field of view 71corresponds to the field of view II of UN/ECE R46, i.e., a main mirrorfield of view. However, the target field of view may also correspond toany other field of view, either a legally required field of view or awished field of view, i.e., a field of view predetermined by themanufacturer or user.

At a rear edge of the driver's cabin 61 of the truck 60, the referencetransducer 50 shown in FIG. 1 is arranged. As shown in FIG. 2, thereference transducer 50 is located in the recording cone 11 of the imagecapture unit 60. The reference transducer 50 may also be attached to thevehicle built-up 62, provided that the built-up is a rigid built-up.

FIG. 3 shows the vehicle environment of FIG. 2 in a side view. As shownin FIG. 3, the recording portion 11 of the image capture unit 10 doesnot only expand in a horizontal plane which is parallel to the roadsurface from the image capture unit 10 to the rear of the truck 60, butalso expands to the rear in a plane which is orthogonal to the roadsurface and parallel to the left truck vehicle outer wall. The targetfield of view 71 is shown in FIG. 3 as big black line in the plane ofthe road surface. As further shown in FIG. 3, the reference transduceris arranged in an upper rear left corner of the traction machine of thetruck 60 and is captured by the recording cone 11 of the image captureunit 10.

FIG. 4 shows the reproduction unit 40 shown in FIG. 1. In FIG. 4, thereproduction unit 40 shows the ideal vehicle environment shown in FIGS.2 and 3. The person schematically depicted in FIG. 4 is not shown inFIGS. 2 and 3. In FIG. 4, for sake of clearness, only the tractionmachine of FIGS. 2 and 3 is depicted. As it can be taken from FIG. 4,the reference transducer 50 is arranged at the traction machine of thetruck 60 via a reference transducer supporting element 53. Specifically,the reference transducer 50 is attached to an end of the referencetransducer supporting element 53 protruding from the traction machine ofthe truck 60 which end is distal from the vehicle. The referencetransducer 50 may be a light reflecting element or a lamp which emitslight to the front of the truck 60.

FIG. 5 shows an image sensor 20 as it is present in the image captureunit 10 shown in FIG. 1 and schematically shows a verification processwhich is performed by the image processing unit 30 and wherein averification of the recording portion 11 of the image capture unit 10 ora read-out portion 22 of the image sensor occurs by comparing areference transducer current position 52 and a reference transducertarget position 51 on the image sensor 20.

The image sensor 20 has a rectangular shape with a longer extension inthe up-and-down-extension than in the left-and-right-extension in FIG.5. On the image sensor 20, the entire vehicle environment located in therecording cone 11 is depicted. A part of the image data shown on theimage sensor 20 is read out as an image read-out portion 22 (seerectangular with fine dashed line) and is transmitted to thereproduction unit 40 for displaying. It is also possible to transmit theimage data of the entire image sensor 20 to the reproduction unit 40 fordisplaying.

In a left upper corner of the image read-out portion 22, an imageanalysis portion 21 is arranged (see rectangular with roughly dashedline). In the image analysis portion 21, a reference transducer targetposition 51 is indicated. The reference transducer target position 51 onthe image sensor 20 corresponds to the position on the image sensor 20at which the reference transducer 50 should be depicted, if therecording portion 11 of the image capture unit 10 is located in therequired and wished adjustment, respectively. In the required and wishedadjustment of the recording portion 11 of the image capture unit 10,respectively, the driver sees the required and wished vehicleenvironment, respectively, on the reproduction unit 40, such as, forexample, the required and wished target field of view 71, respectively.

In the image analysis portion 21, further, a reference transducercurrent position 52 is depicted. The reference transducer currentposition 52 on the image sensor 20 corresponds to the position on theimage sensor 20 where the reference transducer 50 is actually depicted,if the image capture unit 10 captures the vehicle environment. As shownin FIG. 5, the reference transducer current position 52 does not lie inthe same position as the reference transducer target position 51. As thereference transducer target position 51 has a fixed geometric relation73 to the target field of view 71, a current field of view 72 is alsoshown in a displaced manner in view of the target field of view 71 onthe image sensor 20 of the image capture unit 10, and, in this case, thedriver can only partly see/view into the required and wished vehicleenvironment, respectively (see overlapping portion of the target fieldof view 71 and the current field of view 72 in FIG. 5), on thereproduction unit 40.

The deviation of the reference transducer current position 52 and thereference transducer target position 51 on the image sensor 20 isdetected in the embodiment shown in FIG. 5 by a suitable computerprogram stored in the image processing unit 30, such as, e.g. by imagerecognition, and is shown to the driver by an audio warning or acorresponding display on the reproduction unit 40 or the dashboard.Then, for example, the driver may correct the deviation of the referencetransducer current position 52 to the reference transducer targetposition 51 manually by adjusting the image capture unit 10 such thatthe reference transducer current position 52 is equal to the referencetransducer target position 51. In a further or an alternative step tothe output of a signal, however, the image processing unit 30 may alsocorrect the error in the depiction on the image sensor, i.e., that thereference transducer current position 52 is unequal to the referencetransducer target position 51, on its own and, thus, may calibrate theindirect view system. A calibration of the recording portion 11 of theimage capture unit 10 may occur automatically by the image processingunit 30. In general, the determination whether the reference transducercurrent position 52 is equal to the reference transducer target position51 is started either upon a signal, such as a corresponding command ofthe driver, upon a vehicle event or by a corresponding calibrationprogram. A vehicle event may be the starting of the vehicle, theswitching on of the ignition, the coupling of a trailer, etc. Acalibration program performs a determination of the reference transducercurrent position 52 by means of a corresponding software in a clockedmanner, compares the reference transducer current position 52 with thereference transducer target position 51 and corrects the referencetransducer current position 52 autonomously such that it coincides withthe reference transducer target position 51.

As it is further shown in FIG. 5, a reference transducer target portion23 is defined around the reference transducer target position 51. Thereference transducer target portion 23 defines an area on the imagesensor 11 in which the reference transducer 50 has to be located atleast, in order to be able to capture the required and wished fields ofview, respectively, with the image capture unit 10, to depict them onthe image sensor 11 and to show them on the reproduction unit 40. Thereference transducer target portion 23 is defined in advance by thevehicle manufacturer or the view system manufacturer and usuallycomprises a portion which is symmetrical around the reference transducertarget position 51. A non-symmetric extension of the referencetransducer target portion 23 around the reference transducer targetposition 51 is also conceivable. Therefore, it may also be sufficientthat the reference transducer current position 52 is displaced into thereference transducer target portion 23, in order to calibrate the viewsystem 1, but does not have to exactly lie on the reference transducertarget position 51.

In FIG. 6, the reproduction unit 40 is shown whose display correspondssubstantially to the display of the reproduction unit of FIG. 4.However, in FIG. 6, a reference transducer 50 is shown which is attachedto a lower rear right corner of the driver's cabin 61 of the truck 60.The reference transducer 50 in FIG. 4 is a kind of crossline which isattached to the driver's cabin outer wall. For example, the referencetransducer 50 may be a permanent adhesive label/sticker or may beattached during vanishing the truck 60 at the driver's cabin outer wall.The reference transducer, thus, is permanently attached to the driver'scabin outer wall. Alternatively, however, the reference transducer 50may also be a (releasable) adhesive label/sticker, may be attachable viaa magnetic base to the driver's cabin/truck outer wall or may beconfigured otherwise releasably from the driver's cabin/truck outer wallsuch that it is fixed only on demand, i.e. for a planned verificationand, if so, calibration of the indirect view system 1, to the body ofthe truck. Furthermore, the reference transducer may be attached to allimaginable and suitable locations at the body of the truck 60, however,may also be attached to a fixedly defined part of a vehicle built-up,such as, for example, a box body. Alternatively, special shapes of thevehicle body of the truck (e.g., the wheel, the rear edge of thedriver's cabin 61 or the built-up 62) may form the reference transducer50 itself.

FIG. 7 shows again the reproduction unit 40 of FIG. 6 and a verificationprocess which is performed by the image processing unit 30 and wherein averification of the recording portion 11 of the image capture unit 10occurs by comparison of a reference transducer current position 52 and areference transducer target position 51 on the reproduction unit 40,e.g. either digitally by an overlay or manually by applying a foil oneach of which the reference transducer target position is defined. Theoverlay and the foil, respectively, correspond presently to theverification unit.

While in FIG. 6 only the target situation is shown on the reproductionunit 40, in FIG. 7, the target situation and the current situation areshown on the reproduction unit 40. Specifically, it is shown in FIG. 6that the reference transducer 50 is located in the target situation atthe reference transducer target position 51 and in the current situationat the reference transducer current position 52. With a referencetransducer current position 52 which is displaced in view of thereference transducer target position 51, also the current field of view72 is displaced in view of the target field of view 71.

The deviation of the reference transducer current position 52 and thereference transducer target position 51 on the image sensor 20 isdetected in the embodiment shown in FIG. 6 by a suitable computerprogram which is stored in the image processing unit 30, such as, forexample, by image recognition, and is shown to the driver on thereproduction unit 40 by laying the target situation over the currentsituation. If so, the display of the current situation deviating fromthe target situation can be shown to the driver on the reproduction 40also by an additional signal, such as by an audio warning or acorresponding display on the reproduction unit 40 or the dashboard.Then, for example, the driver may correct the deviation of the referencetransducer current position 52 to the reference transducer targetposition 51 manually by adjusting the image capture unit 10, such thatthe reference transducer current position 52 is equal to the referencetransducer target position 51. In a further or alternative step to thesignal output, however, the image processing unit 30 may also correctthe error in the depiction on the image sensor, i.e. that the referencetransducer current position 52 is unequal to the reference transducertarget position 51, on its own by means of a suitable calibrationprogram and, thus, may calibrate the indirect view system. A calibrationof the recording portion 11 of the image capture unit 10 by the imageprocessing unit 30 may occur automatically. In general, thedetermination whether the reference transducer current position 52 isequal to the reference transducer target position 51 is either startedupon a signal, such as a corresponding command of the driver, upon avehicle event or upon a corresponding calibration program. A vehicleevent may be the starting of the vehicle, the switching on of theignition, the coupling of a trailer, etc. A calibration program performsa determination of the reference transducer current position 52 by meansof a corresponding software in a clocked manner, compares the referencetransducer current position 52 with the reference transducer targetposition 51 and corrects the reference transducer current position 52 onits own such that it coincides with the reference transducer targetposition 51.

While it is shown in FIG. 6 that the reference transducer 50 is arrangedat the rear portion of the driver's cabin 61, FIG. 7 shows that thereference transducer 50 is arranged at a rear portion of a built-up 62of the truck 60.

In FIG. 8, a flow diagram is shown which describes the verificationprocess and calibration process, respectively. In step S10, an imagecapture unit 10 which has at least one image sensor 20 and is configuredfor capturing image data of at least one recording portion 11 around thetruck, an ECU as image processing unit 30 which is configured forprocessing the image data captured by the image capture unit 10, and amonitor as reproduction unit 40 which is configured for reproducing theimage data processed by the image processing unit 30, are provided.Further, in step S10, a reference transducer is provided which isarranged at a defined position at the truck 60 such that the referencetransducer 50 lies in a recording portion of the image capture unit 10during operation of the view system 1 and is depicted on the imagesensor 20.

In step S20, a reference transducer target position 51 iscorrespondingly defined/determined on the image sensor 20 where thereference transducer 50 is depicted in an ideal vehicle environment.

In step S30, the image capture unit captures image data of the recordingportion 11 around the vehicle 60 on the image sensor 20 which comprisethe reference transducer 50.

In step S40, the image read-out portion 22 read out from the image dataof the image sensor 20 is shown on the reproduction unit 40.

In step S50, a reference transducer current position 52 of the referencetransducer 50 is determined on the image sensor 20 and, in step S60, thereference transducer current position 52 and the reference transducertarget position 51 are compared with each other to that effect whetherthe reference transducer current position 52 is equal to the referencetransducer target position 51 or not (S70).

If the reference transducer current position 52 is equal to thereference transducer target position 51 (YES in S70), the verificationprocess returns to step S50 and determines the reference transducercurrent position 52. The re-determination of the reference transducercurrent position 52 may either occur upon a signal, such as, forexample, a manual signal by the driver or an automatically generatedsignal, such as upon elapse of a certain time span, or may occurdirectly after determination that the reference transducer currentposition 52 is equal to the reference transducer target position 51,without time delay, i.e., in an inquiry program loop.

If the reference transducer current position 52 is not equal to thereference transducer target position 51 (NO in S70), the process eitherproceeds to step S71 and outputs a signal to the driver which shows thedriver the deviation of the reference transducer current position 52relative to the reference transducer target position 51, or proceeds tostep 72 in which the recording portion 11 of the camera 10 iscalibrated, i.e. corrected such that the reference transducer currentposition 52 is equal to the reference transducer target position 51. Itis also conceivable that steps S71 and S72 occur timely subsequently,i.e., firstly, that a signal is output to the driver which shows thedeviation of the reference transducer current position 52 to thereference transducer target position 51 and, directly following to theoutput of the signal, the correction of the reference transducer currentposition 52 occurs such that the reference transducer current position52 is equal to the reference transducer target position 51.

The process of FIG. 8 is terminated after step S71 and, after step S72,may either return again to step S70, in order check whether thereference transducer current position 52 is equal to the referencetransducer target position 51, or may alternatively also be terminatedafter step S72.

It is explicitly stated that all features disclosed in the descriptionand/or the claims are intended to be disclosed separately andindependently from each other for the purpose of original disclosure aswell as for the purpose of restricting the claimed invention independentof the composition of the features in the embodiments and/or the claims.It is explicitly stated that all value ranges or indications of groupsof entities disclose every possible intermediate value or intermediateentity for the purpose of original disclosure as well as for the purposeof restricting the claimed invention, in particular as limits of valueranges.

Thus, while there have shown and described and pointed out fundamentalnovel features of the invention as applied to a preferred embodimentthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the devices illustrated, and intheir operation, may be made by those skilled in the art withoutdeparting from the spirit of the invention. For example, it is expresslyintended that all combinations of those elements and/or method stepswhich perform substantially the same function in substantially the sameway to achieve the same results are within the scope of the invention.Moreover, it should be recognized that structures and/or elements and/ormethod steps shown and/or described in connection with any disclosedform or embodiment of the invention may be incorporated in any otherdisclosed or described or suggested form or embodiment as a generalmatter of design choice. It is the intention, therefore, to be limitedonly as indicated by the scope of the claims appended hereto.

What is claimed is:
 1. A method for verifying an indirect view system ofa vehicle, comprising providing (S10) at least one image capture unitwhich has at least one image sensor and is configured for capturingimage data of at least one recording portion around the vehicle,providing (S10) at least one image processing unit which is configuredfor processing the image data captured by the image capture unit,providing (S10) at least one reproduction unit which is configured forreproducing the image data processed by the image processing unit,providing (S10) at least one reference transducer at a defined positionat the vehicle such that the reference transducer lies in the recordingportion of the image capture unit and is depicted on the image sensor,wherein the reference transducer is defined at a reference transducertarget position on the image sensor (S20), capturing (S30) of image dataof the at least one recording portion around the vehicle on the imagesensor which comprise the reference transducer, reproducing (S40) atleast one image read-out portion read out from the image data of theimage sensor on the reproduction unit, determining (S50) a referencetransducer current position of the reference transducer on the imagesensor, and comparing (S60, S70) the reference transducer currentposition and the reference transducer target position to that extentwhether the reference transducer current position is equal to thereference transducer target position or not.
 2. The method according toclaim 1, wherein the reference transducer target position has a fixedgeometric relation to at least one target field of view captured by theimage capture unit.
 3. The method according to claim 1, wherein at leastthe reference transducer current position is depicted on thereproduction unit and the comparing (S60, S70) occurs on thereproduction unit.
 4. The method according to claim 1, wherein thecomparing (S60, S70) occurs in the image processing unit.
 5. The methodaccording to claim 2, wherein at least the reference transducer currentposition is depicted on the reproduction unit and the comparing (S60,S70) occurs on the reproduction unit, the method further comprisingcomparing a current field of view and a target field of view.
 6. Themethod according to claim 4, wherein the comparing of the referencetransducer current position and the reference transducer target positionoccurs by the image processing unit in at least one image analysisportion of the image sensor.
 7. The method according to claim 6, whereinthe image read-out portion comprises the image analysis portion.
 8. Themethod according to claim 1, further comprising the step of outputting asignal to the driver, if the reference transducer current position isunequal to the reference transducer target position.
 9. The methodaccording to claim 1, further comprising the step of performing acalibration action, if the reference transducer current position isunequal to the reference transducer target position.
 10. The methodaccording to claim 9, wherein the calibration action comprises theadjustment of the recording portion of the image capture unit, such thatthe reference transducer current position is equal to the referencetransducer target position.
 11. The method according to claim 10,wherein the adjustment of the recording portion of the image captureunit occurs by aligning of at least one part of the image capture unitand/or by adapting the at least one image read-out portion on the imagesensor.
 12. The method according to claim 9, wherein the calibrationaction occurs by a signal received from the image processing unit. 13.The method according to claim 2, wherein the target field of view is alegally prescribed field of view.
 14. The method according to claim 1,wherein the indirect view system is a mirror replacement system.
 15. AnIndirect view system of a vehicle which is configured for performing themethod according to claim 1, the system comprising: the at least oneimage capture unit, which comprises an image sensor and which isconfigured for capturing image data of at least one recording portionaround the vehicle, the at least one image processing unit which isconfigured for processing the image data captured by the image captureunit, the at least one reproduction unit which is configured forreproducing the image data processed by the image processing unit, theat least one reference transducer which is configured such that it isattachable to a defined position at the vehicle and, in a state of theindirect view system mounted on the vehicle, lies in a recording portionof the image capture unit and is depicted on the image sensor, whereinthe reference transducer is depicted on the reference transducer targetposition on the image sensor, and at least one verification unit whichis configured for defining a reference transducer target position andfor determining a reference transducer current position on the imagesensor.
 16. The indirect view system according to claim 15, wherein theview system further comprises a calibration unit which is configured forperforming a calibration action.
 17. The indirect view system accordingto claim 15, wherein the reference transducer comprises a geometricpattern.
 18. The indirect view system according to claim 15, wherein thereference transducer reflects light.
 19. The indirect view systemaccording to claim 15, wherein the reference transducer is a lightsource.
 20. The indirect view system according to claim 19, wherein thelight source is a lamp which exists at the vehicle.
 21. The indirectview system according to claim 19, wherein the light source isconfigured for indicating a pollution of the optics of the image captureunit on the reproduction unit.
 22. The indirect view system according toclaim 15, further comprising at least two capture units, wherein areference transducer is respectively associated with each capture unitor wherein a common reference transducer is associated to the captureunits.
 23. The indirect view system according to claim 15, wherein theview system is a mirror replacement system.
 24. A vehicle with anindirect view system according to claim 15, wherein the image captureunit is arranged in a supporting element which extends distally from thevehicle.
 25. The vehicle according to claim 24, wherein the referencetransducer is attached at an outer side of the vehicle driver's cabin.26. The vehicle according to claim 24, wherein the reference transduceris attached to a side surface of the vehicle.
 27. The vehicle accordingto claim 24, wherein the vehicle is a commercial vehicle and thereference transducer is attached to a front surface of the vehicle. 28.The vehicle according to claim 24, wherein the reference transducer isattached to a vehicle built-up of the vehicle.
 29. The vehicle accordingto claim 24, wherein the reference transducer is attached via areference transducer supporting element to the vehicle.
 30. The vehicleaccording to claim 24, wherein the reference transducer is releasablyconnected to the vehicle.